A representative example of construction equipment having a swing body driven by a motor is a hybrid excavator of which swing energy is regenerated.
FIG. 1 is a block diagram illustrating an apparatus to drive a swing body using a conventional hydraulic motor.
FIG. 1 illustrates an apparatus to drive a swing body using a hydraulic swing motor, of an excavator. At step 180, an operator 110 manipulates a joystick 120. An operating signal generated in accordance with the manipulation, for example, a pilot pressure is transferred to the main control valve 130 from the joystick 120 at step 182 and thereby, letting a swing spool of the main control valve 130 move. At step 184, the main control valve 130 supplies the hydraulic swing motor 140 with oil pressure. The torque generated by the oil pressure in the hydraulic swing motor 140 is delivered to a swing reduction gear 150 at step 186. At step 188, the swing body 160 is circled by the torque that passed through the swing reduction gear 150. This swing system does not include any special composition measuring swing speed, which is a controlled variable. Thus, there is no other special countermeasure, except for the method that the operator 110 controls the speed by manipulating the joystick while looking at it with his eyes.
However, according to the method illustrated in FIG. 1, it may cause troubles that control performance of the swing body 160 depends heavily on the operator 110's personal capability. A method to drive an apparatus to drive the swing body easily without relying on the operator 110's capability is required.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.